public String writeGraph() { java.io.OutputStream output = new java.io.OutputStream() { private StringBuilder stringBuilder = new StringBuilder(); @Override public void write(int chr) throws java.io.IOException { stringBuilder.append((char) chr ); } @Override public String toString() { return stringBuilder.toString(); } }; try { graph.io(IoCore.graphson()).writer().create().writeGraph(output, graph); } catch (java.io.IOException e) { e.printStackTrace(); } String wellformedJson = "[" + String.join(",\n", (CharSequence[]) output.toString().split("\n")) + "]"; com.google.gson.Gson gson = new GsonBuilder().setPrettyPrinting().create(); com.google.gson.JsonParser jp = new JsonParser(); com.google.gson.JsonElement je = jp.parse(wellformedJson); return gson.toJson(je); }